“ Garra mondica,” a ghost of evolutionary past.

Iranian “ G. mondica ” was considered endemic to the springs of Tang-e-Mohr, Konar Siyah, and Firozabad in the Mond drainage. In fact, “ G. mondica ” is a long-extinct species, and only its mitochondrial genome has survived in a few populations of G. rufa as a remnant of its evolutionary past. “ Garra mondica ” was described as a separate species based on mtDNA alone; none of the morphological characters proposed as diagnostic could be confirmed. Genome-wide SNP data examined for “ G. mondica ” show that its nuclear DNA, which codes for all its morphology, ecology, and behaviour, is identical to that of G. rufa . Only the mitochondrial genome of G. mondica survived the intense introgression of G. rufa after it invaded the Mond drainage. As “ G. mondica ” was described based on G. rufa individuals containing mitochondrial DNA of the extinct “ G. mondica,” it is treated as a synonym of G. rufa . Similar discordances between nuclear DNA and mtDNA have been found in G. gymnothorax, and the situation should be carefully investigated in G. amirhosseini, G. hormuzensis, G. meymehensis, and G. tiam . All these species occur in sympatry or proximity to G. rufa .

Further reading. Sayyadzadeh et al. 2015b (description); Zamani-Faradonbe et al. 2021b (characters, distribution).